1. Field of the Invention
This invention relates to a vacuum disk. More particularly, it relates to a vacuum disk having a manually created high vacuum.
2. Description of the Prior Art
Suction cups are formed of a flexible and resilient material formed into a concavity. When the material is pressed firmly against a flat surface, the material flattens and most of the air in the concavity is driven out. In this way, a partial vacuum is created. However, an externally applied force in excess of about four (4) ounces is about all that is needed to defeat the vacuum and separate the suction cup from the flat surface.
Thus, a conventional suction cup can be used to hold light, unbreakable objects such as washcloths, pictures having frames formed of a high impact plastic, and the like. They gradually lose their vacuum over time and cannot be used to hold objects that might break if dropped.
An improved suction cup includes a rigid frame that surrounds a flexible and resilient conventional suction cup. A hook from which a washcloth, picture frame, or the like may be hung is pivotally mounted to the rigid frame. After the flexible and resilient part of the structure is pressed tightly against a flat surface, the hook is pivoted into its operable position. The hook includes a cam that bears against the rigid frame so that when the hook is pivoted into its operable position, a cammed surface thereof drives the rigid frame into tightly overlying relation to the flexible and resilient part of the suction cup. This enhances the vacuum within the space surrounded by the flexible and resilient part of the structure. An externally applied force of three to four pounds is needed to separate the improved suction cup from its mount.
However, it has been established that the vacuum created by the improved suction cup does not endure for more than a few hours. What is needed, then, is an improved device that has greater strength than the just-described improved suction cup and which does not lose its holding power so quickly.
However, in view of the prior art taken as a whole at the time the present invention was made, it was not obvious to those of ordinary skill how the identified needs could be fulfilled.